What is the main function of the trachea?

The main function of the trachea is to facilitate the passage of air to and from the lungs, which aligns with the selected answer. The trachea, commonly known as the windpipe, is a crucial part of the respiratory system. It connects the larynx (voice box) to the bronchi, which lead to the lungs. As air flows through the trachea, it travels towards the bronchial tubes and ultimately reaches the alveoli, where gas exchange occurs.

In context, filtering incoming air is also a function associated with the trachea, but it primarily serves to clean and humidify air as it travels. Producing sound is a function of the vocal cords located in the larynx, not the trachea itself. Gas exchange is a process that takes place in the alveoli of the lungs, not within the trachea. Therefore, while related to respiratory functions, these roles do not accurately describe the primary duty of the trachea, which is to move air efficiently into and out of the lungs.